1. Technical Field
The present invention relates to a method for manufacturing a light emitting diode (LED) chip and an LED light source module, and more particularly, to a method for manufacturing an LED chip for a chip on board (COB) and a method for manufacturing an LED light source module using the COB.
2. Discussion of the Related Art
As technologies for liquid crystal displays (LCDs) have been developed, needs for products with high color reproduction and environment-friendly characteristics are increased. Studies for products employing an LED backlight have been actively performed. An LED has long life, and low power consumption. The LED requires no additional inverter, and the LED can uniformly emit light. In addition, the LED is lightweight and thin. Therefore, the LED has been frequently used as backlight light sources for LCDs.
A backlight light source module is manufactured in various shapes including a bar shape or a circular shape, by packaging respective LED chips and mounting the LED packages on a printed circuit board in accordance with intended uses. However, when the respective LED packages are mounted to the printed circuit board, the total height of the backlight light source module is increased and the manufacturing costs are also increased. Since a plurality of interfacial surfaces each having different thermal and electrical characteristics overlap each other, a heat radiation or electrical resistance characteristic is lowered.
A ‘chip on board’ (COB) technique has been studied. LED chips are individually packaged and the LED packages are then mounted on a printed circuit board. In the COB technique, LED chips are directly mounted on a printed circuit board to reduce electrical and thermal losses in the interfacial surfaces. Accordingly, a more efficient LED light source module structure can be configured.
When the COB technique is used, material costs can be reduced and higher efficiency can also be achieved from even a smaller number of LEDs.
According to the COB technique, the characteristics of the respective LED chips can be evaluated only after the LED chips have been mounted on the printed circuit board. In order to obtain color uniformity and electrical uniformity of an LED light source module having a plurality of LED chips, the LED chips are mounted on a printed circuit board and then tested for their optical and electrical characteristics.
When there are any LED chips having desired characteristics, the undesired chips should be removed through a rework process. However, when the rework process has been completed, it is difficult to keep a normal shape of the printed circuit board and to obtain uniform optical and electrical characteristics of the LED light source module. Furthermore, the efficiency of productivity can be lowered due to the increase in manufacturing time and material costs.